Income Taxes - Income Tax Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Provision for current income taxes
Federal	$ 12,207	$ 11,308	$ 1,330
State	3,044	2,292	388
Total provision for current income taxes	15,251	13,600	1,718
Provision (benefit) for deferred income taxes, net
Federal	(1,476)	(1,109)	2,114
State	(372)	89	161
Total provision (benefit) for deferred income taxes, net	(1,848)	(1,020)	2,275
Total provision for income taxes	$ 13,403	$ 12,580	$ 3,993